With the rapid development of broadband services, the user's demand for access network bandwidth has increased significantly. Passive Optical Network (PON) is an important technical approach for user's access. FIG. 1 shows a schematic diagram of a passive optical network system architecture in the related art. As shown in FIG. 1, in a PON system, an Optical Line Terminal (OLT) is connected to an optical splitter through a backbone optical fiber, and the optical splitter is connected to multiple Optical Network Units (ONUs) through a branch optical fiber. Traditional PON technologies, such as Gigabit PON (GPON), Ethernet PON (EPON), 10 Gigabit PON (XG-PON1) and 10 Gbps EPON (10GEPON), adopt Time Division Multiplexing (TDM)/Time Division Multiplexing Access (TDMA) technology. The OLT and the ONU communicate with each other by a wavelength pair. NG-PON2 adopts Time Division Multiplexing & Wavelength Division Multiplexing PON (TDM & WDM PON; TWDM-PON for short). A wavelength dimension and a bandwidth at the OLT are increased, and it is required that each ONU works only at one wavelength. The ONU can select one wavelength for communication by wavelength tuning. IEEE NG-EPON also chooses to use multiple wavelengths to achieve bandwidth extension, and multi-channel bonding technology is proposed to be used to increase the bandwidth. The ONU can support simultaneous communication on multiple channels.
As for the multi-channel bonding, traditional DSL and Ethernet simply perform bonding on multiple physical channels to increase bandwidth, as needed; and generally, after the multi-channel bonding, the number of the channels will not be changed during communication. As for the PON system, the multiple channels of the ONU refers to multiple optical wavelength channels. Under the condition that the optical device itself consumes a large amount of energy, performing bonding simply on multiple physical channels will cause energy consumption. In view of the above problem in the related art, there is currently no effective solution yet.